Looks amazing when ingeneers uses knowledge in combination with tools. Just wondering if the crossover and correction could be done with a dsp ? . Always thougt that dsp with mic meters away from a speaker is wrong, you cant correct anything after the fact ?.
Whoa!!!
But is the dispersion in the top end created by intentionally adding diffraction around the tweeter, similar to older constant-directivity horns?
But is the dispersion in the top end created by intentionally adding diffraction around the tweeter, similar to older constant-directivity horns?
thanks! EQ of on axis response and xovers can of course be done with a DSP or as an active line level filter. However, the dispersion of each driver cannot be changed by EQ. Only if you have an array of drivers with individual shaping for each driver. This can do active beam forming
Thank you for your answer. That was what I ment with , you can not change things in a speaker after it has happend, so you can not simulate a waveguide in a dsp. And why should you when it looks like you have made it near perfect. What it looks like is, you can measure what happens in the boks and correct the speaker with no time delay ?. Could be fun if you could make dsp (sub)woofer correction with a tweeter as a mic inside the boks, and not a normal mic outside 🙂
This tweeter looks pretty cool!
I did not find any info on the dome material, what is it?
What is the function of the small ring in front of the dome? It looks like something we usually see there to decrease high end dispersion.
I did not find any info on the dome material, what is it?
What is the function of the small ring in front of the dome? It looks like something we usually see there to decrease high end dispersion.
I haven't had a chance to look at the white paper.
Will do as soon as I have the dedicated time. But @5th element and I were working on a coaxial. Design is finished:
http://www.5een.co.uk/SB17Coax.htm
I had considered a wide dispersion tweeter in a waveguide for controlled directivity up to an wider beam-width, though Matt feels that 45 degree would be better.
My question is:
What made you settle on ~75 degree as the beam width? Is it it preferable to 80, 60, or 45 (x)? Or is that how it fell into place after the optimization process?
My room is 6.4m L x 4.8m W with asymmetric cathedral ceilings (2.4-3.2m). We know controlled directivity allows for consistent tonal balance in horizontal axis, but wider dispersion is better for larger rooms I think, in terms of a sense of spaciousness.
But I have no empirical evidence for this (yet)
best regards,
Thanh
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@lrisbo
Thanks for sharing the paper. Fascinating how you are leveraging modern modelling techniques to deliver such impressive results.
The paper notes "Tweeter and waveguides are typically optimised for on axis and polar responses in infinite baffle (2pi). However, the responses when measure in a box in free field (4pi) will be much different due to the finite sized box. For this reference design we have chosen to optimise the tweeter waveguide to match not only the specific tweeter but also the specific box to be used". By specific box it is meant the external dimensions and edge rounding radius, or is the internal volume somehow being considered as well? I imagine it's the former, but you have gone so far that I could be easily missing something else.
Can we expect a future paper portraying the use of the new tweeter with the PTT6.5M and a larger woofer below? My simplistic brain envisions a SPK16 sized box with tweeter and midrange sitting atop a separate box with the larger woofer. Brighter brains will likely outdo that🙂
Thanks for sharing the paper. Fascinating how you are leveraging modern modelling techniques to deliver such impressive results.
The paper notes "Tweeter and waveguides are typically optimised for on axis and polar responses in infinite baffle (2pi). However, the responses when measure in a box in free field (4pi) will be much different due to the finite sized box. For this reference design we have chosen to optimise the tweeter waveguide to match not only the specific tweeter but also the specific box to be used". By specific box it is meant the external dimensions and edge rounding radius, or is the internal volume somehow being considered as well? I imagine it's the former, but you have gone so far that I could be easily missing something else.
Can we expect a future paper portraying the use of the new tweeter with the PTT6.5M and a larger woofer below? My simplistic brain envisions a SPK16 sized box with tweeter and midrange sitting atop a separate box with the larger woofer. Brighter brains will likely outdo that🙂
yes, its the external box shape that matters for the diffraction. the internal shape matters for the acoustic modes inside the box but that is a different story 🙂
Will it be possible to DIY the SPK16? Meaning to be able to buy a set of drivers and a waveguide and plans? So we can have an end game speaker for the common man?
very good questions. To me the super side disperions simply sounds more spacious and with more air. The soundstage is in 3D. I do not hear it as brighter as some would suspect. It depends on the recording of course and how it was mixed (I prefer straight AB stereo recordings without further processing or mixing). As for why it ended at 70 deg: I asked the optimiser for wide and smooth but also to be be able cross to the woofer seamlessly.
Sorry for going slightly off topic, but what exactly was the final solution mentioned in the text?
Purifi subwoofer next? 10Hz Rs and 20mm excursion? Crosses up to 400hz? Where are you keeping the sound wizards imprisoned(?) and what are they cooking up now?
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hoping for samples Q4. but the world is more unpredictable now than before...